GPG cheat sheet

Key Management

List all of your (secret) keys

gpg --list-secret-keys

List all of the public keys you have imported

gpg --list-keys

List all the keys in a GPG file

# GPG version 1.x
gpg file.gpg
gpg --keyid-format 0xlong file.gpg

# GPG version 2.x
????

Delete a key-pair

Delete the private key first, then the public key:

gpg --delete-secret-key "User Name"
gpg --delete-key "User Name"

Delete a public key

gpg --delete-key "name of key"

Import a public key

gpg --import pubkeyfile

Import a public/private key-pair

gpg --import secretkeyfile

Export a public key

gpg --armor --export 573BEE0C

List the trusted keys in a GPG "trusted DB" file:

gpg ???

Convert a GPG file in ASCII to binary

gpg --dearmor < filename.txt > filename.bin

Remove a key from a GPG "database"

gpg --trustdb-name file ???

Create a new key-pair:

gpg --gen-key

Encrypt

Encrypt a document with another user's public key

To encrypt a document with another joeuser@stanford.edu's public key (the key must already be in your GPG key store):

cat plain.txt | gpg --output encrypted.gpg -a --encrypt --recipient joeuser@stanford.edu

Encrypt a document with a password

gpg -c --armor --cipher-algo AES256 private-file.txt

Signatures

Sign a document (ASCII)

gpg --clearsign document_to_be_signed

Sign a document using key other than the default

gpg --local-user <key's uid> --clearsign document_to_be_signed

Verifiy a signed document

gpg --verify document_to_be_verified

Advanced

To verify signatures GPG needs to know where to find the public keys of the signers. So, unless the public keys are in your default location (usually $HOME/.gnupg/trustedkeys.gpg), you need to indicate that file of trusted public keys.

To verify that Release.gpg is the correct signature for file Release, do this:

gpg  --keyring /var/lib/debmirror/trustedkeys.gpg --verify Release.gpg Release
gpgv --keyring /var/lib/debmirror/trustedkeys.gpg Release.gpg Release

To verify an InRelease file:

gpg  --keyring /var/lib/debmirror/trust --verify InRelease
gpgv --keyring /var/lib/debmirror/trustedkeys.gpg InRelease

To display the keyids for the signers of a signature file

gpg -vv file.sig

APT

List keys

apt-key --keyring /etc/apt/trusted.gpg list

Remove a key

apt-key --keyring /etc/apt/trusted.gpg remove <KEYID>

To download a key from the Debian Key Server

gpg --keyserver http://keyring.debian.org/ --recv-keys <KEYID> --trustdb-name /tmp/trustdb.gpg